Not at all. Also your first point makes little sense since adlo and aspected benefic have different potencies and there you're only aribitrarily comparing their shields as % of the base potency for whatever reason. Adlo is 600 potency 70% of the time (if we go with 30% crit rate and assume that a crit enhances your skill by 50% of its base potency) and 1350 potency 30% of time = 825 avg potency. Aspected Benefic is 262.5 + 341.25 shield = 603.75 potency 70% of the time and 906 30% of the time when it crits = 694 avg potency. True, it's instant, but that's doesn't really change anything since it's on GCD. AST's regen now is on par with WHM's regen, it should've been this way from the start. Disable has 6 seconds duration but a lower cd than virus. It's in no way better or worse, it's just different and may be more or less efficient depending on mechanics.
Synastry is OP. It has to be. It's the only healing CD that increases an AST healing output and if we consider that AST has no oGCD abilities that can be conveniently used on CD like asylum/assize and all the fancy Aetherflow skills a SCH has (indomitability and assize are stupidly powerful emergency skills, deployment is the most powerful tool for damage mitigation ecc.), it's just fair. CU is now finally useful but it still poses restrictions that asylum/sacred soil don't, so you can't use it as freely. Again, fair trade-off.
Astrologian is now a real healer. It's not as good as whm or sch in their respective fields, which is fine since it brings more utility thanks to cards...unless rng really hates you. Each healer will be able to shine in particular encounters and I can see different healers combinations being optimal for different fights which was ultimately the dev's objective. Now only one issue remains: is AST capable of increasing the raid dps enough, be it via own's dps or party buffs, to be at least as desirable as sch for raid progression? I honestly have no idea and rng can be a real issue here. We'll know when the next raid is released I guess.
If I keep drawing spires when my dps don't need it, it's no use. If I keep drawing spears, I'm just wasting my time. Let me tell you that dps don't love when we use cards on them that will mess their cd alignment. RNG is an issue and this is proved by the fact that SE gave as tools to control it. Sadly, these tools are not enough.